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Publication No. 16-09-044 (July 2016) Page i
Dioxins, Furans, and Dioxin-Like PCB Congeners: Ecological Risk Calculation Methodology for Upland Soil
Implementation Memorandum No. 13
Date: July 12, 2016
To: Interested Persons
From: Jeff Johnston, Manager
Information & Policy Section
Toxics Cleanup Program
Contact: Arthur Buchan, Toxicologist, arthur.buchan@ecy.wa.gov, 360.407.7146
Policy & Technical Support Unit, Toxics Cleanup Program
Attachments: None
Accommodation Requests: To request ADA accommodation including materials in a format for
the visually impaired, call Ecology’s Toxics Cleanup Program at 360-407-7170. Persons with
impaired hearing may call Washington Relay Service at 711. Persons with speech disability may
call TTY at 877-833-6341.
Washington State Department of Ecology Toxics Cleanup Program Implementation Memo #13
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Table of Contents
List of Tables, Figures, & Equations .......................................................................... iii
Acronyms ...................................................................................................................... iv
1.0 Purpose and Applicability ..................................................................................... 1
2.0 Background ............................................................................................................ 1
2.1 Dioxin/Furans........................................................................................................ 1
2.2 PCBs .................................................................................................................... 2
2.3 Aryl Hydrocarbon Receptor .................................................................................. 4
2.4 Screening Levels for Dioxins, Furans, and PCBs ................................................. 5
2.5 Summary of TEQ Methodology............................................................................. 5
2.6 TEQ Methodology for Ecological Risk Assessment .............................................. 7
3.0 General Procedures for Determining Compliance for Dioxins, Furans, and PCBs using the TEE Table Values in WAC 173-340-900 ............................................ 9
4.0 Step-by-Step Procedure for Determining Compliance for Mixtures of Dioxins, Furans, and PCBs Using the TEE Table Values in WAC 173-340-900 and EPA Method 1668 ................................................................................................................ 11
5.0 How do I determine if dioxins, furans or PCBs are contaminants of ecological concern? ...................................................................................................................... 15
6.0 What method do I use to analyze PCBs? ........................................................... 17
7.0 Step-by-Step Procedure for Determining Compliance for Mixtures of PCBs Using the Tables in WAC 173-340-900 and EPA Method 8082 or EPA Method 1668 ...................................................................................................................................... 19
8.0 Step-by-Step Procedure for Calculating Site-Specific Dioxin, Furan, and PCB Ecologically Protective Cleanup Levels and Determining Compliance (When Using Methods other than MTCA Tables 749-2 or Table 749-3) ............................. 21
9.0 References ............................................................................................................ 25
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List of Tables, Figures, & Equations
Table 1: TEE screening levels for dioxins, furans, and PCBs ......................................... 5
Table 2: PCDD, PCDF, and PCB toxicity equivalency factors for mammals and avians 8
Table 3: General procedures for determining compliance for dioxins, furans, and PCBs using the TEE table values in WAC 173-340-900 ........................................................... 9
Table 4: How to determine if dioxins, furans, or PCBs are contaminants of ecological concern ......................................................................................................................... 15
Figure 1. Chemical structure of PCDDs (dioxins), PCDFs (furans), and dioxin-like PCBs. Numbers by aromatic ring carbons in general structures represent potential chlorine substitutions (USEPA 2008). ............................................................................. 3
Figure 2: Illustration of the toxic response created by any of the 29 dioxin-like congeners (BEC 2012). ................................................................................................... 4
Figure 3: Summary of calculating contaminant levels for use with screening to MTCA Table 749-2 or 749-3. Methods include EPA Method 1613 (USEPA 1994) for Dioxin/Furan analysis, and EPA Methods 1668 (USEPA 2008) and EPA Method 8082 (USEPA 2007) for PCB analysis. .................................................................................. 10
Equation 1: Calculating TEQ concentrations in samples. (Van den Berg et al., 1998) ...................................................................................................................................... 23
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Acronyms
Ah aryl hydrocarbon
CAS Chemical Abstracts Service
DNA deoxyribonucleic acid
EDL estimated detection limit
EQL estimated quantitation limit
KM Kaplan-Meier
MTCA Model Toxics Control Act
PCB polychlorinated biphenyl
PCDD chlorinated dibenzo-p-dioxin
PCDF chlorinated dibenzofuran
PQL practical quantitation limit
QAPP Quality Assurance Project Plan
TCDD 2,3,7,8-Tetrachlorodibenzo-p-dioxin
TCP Toxics Cleanup Program
TEE Terrestrial Ecological Evaluation
TEF toxicity equivalency factor
TEQ toxicity equivalency quotient
USEPA United States Environmental Protection Agency
WAC Washington Administrative Code
Publication No. 16-09-044 (July 2016) Page 1
1.0 Purpose and Applicability
The purpose of this memorandum is to document an interpretation from the Department of
Ecology (Ecology) regarding the different procedures that should be used to calculate site
contaminant concentrations for three types of contaminants when conducting a Terrestrial
Ecological Evaluation under the Model Toxics Control Act (MTCA) (WAC 173-340-7490
through -7494) (Ecology 2007a). The three contaminant types are:
Chlorinated dibenzo-p-dioxins (PCDDs) (2,3,7,8-TCDD is a member of this class);
Chlorinated dibenzofurans (PCDFs); and
Polychlorinated biphenyls (PCBs) (includes both total PCBs and dioxin-like PCBs).
This memorandum specifically pertains to Ecological Risk Assessment and the Terrestrial
Ecological Evaluation (TEE) under MTCA (WAC 173-340-7490 through -7494).
2.0 Background
2.1 Dioxin/Furans
PCDDs and PCDFs (dioxins and furans) are typically present in the environment as complex
mixtures of chemically-related substances (congeners) that differ in the number and location of
chlorine atoms (Ecology, 2007b). There are 210 of these dioxin and furan congeners present in
the environment. The most toxic and best studied congener is 2,3,7,8-Tetrachlorodibenzo-p-
dioxin (TCDD) (Ecology 2007c), which is why TCDD is the standard for comparison in the
methodologies outlined in this memo.
Because dioxin and furan congeners are typically present in the environment as complex
mixtures, scientists developed a toxicity equivalency quotient (TEQ) methodology that evaluates
the toxicity and assesses the risks associated with whole mixtures. With the TEQ method, each
congener is assigned a TEF, or toxicity equivalency factor: the ratio of estimated toxicity for a
particular congener to the toxicity of 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) (Ecology
2007c). The TEQ approach is based on the concept that the various dioxin and furan congeners
act through a common biological mechanism involving the aryl hydrocarbon (Ah) receptor.
Note: MTCA’s Terrestrial Ecological Evaluation established separate screening levels for
dioxins and furans in WAC 173-340-900 (Tables 749-2 and 749-3). However, when Table 749-
2 or Table 749-3 is not used, the dioxins and furans should be treated as one mixture for the
purposes of calculating and comparing to cleanup levels.
As a result, there are two processes to calculate site contaminant levels for dioxins and furans:
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1. Comparing to screening levels using MTCA Table 749-2 or MTCA Table 749-3
(see Section 2.5), and
2. Calculating protective cleanup levels when MTCA Table 749-2 or Table 749-3 is not
used (see Section 2.5).
2.2 PCBs
PCBs are a group of synthetic organic chemicals comprised of 209 individual chlorinated
biphenyl compounds. Commercial mixtures of PCBs were manufactured in the United States
from about 1930 to 1977 and known primarily by their industrial trade names. The most
common trademark in the U.S. was “Aroclor” with a four-digit number (USEPA 2013). The first
two digits usually indicated the parent biphenyl molecule; the last two digits usually indicated
the percent chlorine by weight.
PCBs were used as coolants and lubricants in electrical equipment such as capacitors and
transformers due to their insulating properties, nonflammability, and chemical stability (Ecology
2007b). Although no longer commercially produced in the United States, PCBs may be present
in products and materials produced before the 1979 PCB ban, and as contaminants in products
produced since the use of PCBs was banned (Ecology 2014).
PCBs used in products such as those listed below are chemical mixtures made up of a variety of
individual chlorinated components known as congeners. Examples of products that may contain
PCBs include:
Transformers and capacitors
Other electrical equipment including voltage regulators, switches, reclosers, bushings,
and electromagnets
Oil used in motors and hydraulic systems
Old electrical devices or appliances containing PCB capacitors
Fluorescent light ballasts
Cable insulation
** KEY POINT **
When evaluating if contaminants are of ecological concern:
Treat dioxins and furans as separate chemical mixtures when comparing with the
screening levels in Tables 749-2 or 749-3.
Treat dioxins and furans as one chemical mixture when comparing cleanup levels
through methods other than table values.
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Thermal insulation material including fiberglass, felt, foam, and cork
Adhesives and tapes
Oil-based paint
Caulking
Plastics
Carbonless copy paper
Floor finish
MTCA’s Terrestrial Ecological Evaluation has established two approaches for evaluating the
ecological risks associated with environmental concentrations of PCBs. Both of these
approaches are discussed in Sections 6.0 and 7.0 in this memo:
1. Total PCB Concentration using EPA Method 8082 and
2. Congener Specific Analyses using EPA Method 1668.
Figure 1. Chemical structure of PCDDs (dioxins), PCDFs (furans), and dioxin-like PCBs. Numbers by
aromatic ring carbons in general structures represent potential chlorine substitutions (USEPA 2008).
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2.3 Aryl Hydrocarbon Receptor
The 29 dioxin-like congeners comprise 7 dioxins, 10 furans, and 12 PCBs. The most common
mode of action, or biological mechanism, for these congeners is binding to the aryl hydrocarbon
receptor (Ah receptor).
Figure 2 illustrates how the dioxin or dioxin-like congener binds with the Ah receptor and enters
the nucleus of a cell. The protein dioxin complex then binds to the strands of DNA (switching
certain genes on and off) and causes the toxic response (BEC 2012).
Figure 2: Illustration of the toxic response created by any of the 29 dioxin-like congeners (BEC 2012).
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2.4 Screening Levels for Dioxins, Furans, and PCBs
The screening levels (ecological risk assessment) for dioxins, furans, and PCBs that are included
in the TEE (WAC 173-340-7490 through -7494) are listed in Table 1.
Table 1: TEE screening levels for dioxins, furans, and PCBs
Contaminant TEE Simplified Evaluation
(Table 749-2)
Chlorinated dibenzofurans (total) 3E-06 mg/kg
Chlorinated dibenzo-p-dioxins (total) 5E-06 mg/kg
PCB mixtures (total) 2 mg/kg
Above levels are for both unrestricted and industrial/commercial land use.
Contaminant TEE Site-Specific Evaluation
(Table 749-3)
Chlorinated dibenzofurans (total) Wildlife = 2E-06 mg/kg
Chlorinated dibenzo-p-dioxins (total) Wildlife = 2E-06 mg kg
PCB mixtures Plants = 40 mg/kg Wildlife = 0.65 mg/kg
2.5 Summary of TEQ Methodology
The toxicity equivalency (TEQ) methodology is a tool to assess cumulative toxicity of a complex
mixture of PCDDs, PCDFs, and dioxin-like PCBs, and can be used when conducting an
Ecological Risk Assessment for a cleanup site.
From a toxicological point of view, any calculated screening or cleanup level should apply to all
dioxins, furans, and dioxin-like PCBs, but before 2001 there were very limited data available on
the prevalence of dioxin-like PCBs. Since 2001, more data on the presence of dioxin-like PCBs
have become available. In 2006, maximum levels for the sum of TEQs for dioxins, furans, and
dioxin-like PCBs were set, since this was determined to be the most appropriate approach
(Gueguen et al., 2011). Based on current toxicological methods used to evaluate the toxicity and
assess the risk of complex chemical mixtures, it is recognized that one screening level should
encompass PCDDs, PCDFs, and dioxin-like PCBs. The TEQ methodology was therefore
developed as a tool for assessing the cumulative toxicity of a complex mixture of dioxin-like
PCDDs, PCDFs, and PCBs (USEPA 2008).
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As Table 1 indicates, however, it is important to note that the current MTCA regulations allow
for individual contaminant mixtures (PCDDs, PCDFs, and PCBs) to be compared to the
screening levels listed in WAC 173-340-900 (Tables 749-2 or 749-3) to help establish
contaminants of ecological concern. Several sections in this memo address how to do this:
Using the screening levels in WAC 173-340-900?
Reference the following sections and figure when comparing site contaminant levels to the
screening levels in WAC 173-340-900 (Tables 749-2 or 749-3):
Section 3.0: General procedure for determining compliance for dioxins, furans, and
PCBs using the TEE table values in WAC 173-340-900.
Section 4.0: Step-by-step procedure for determining compliance for mixtures of dioxins,
furans, and PCBs using the TEE table values in WAC 173-340-900 and EPA Method
1668.
Figure 3: Summary of calculating contaminant levels for use when comparing screening
levels to MTCA Table 749-2 or 749-3.
Not using the screening levels in WAC 173-340-900?
Use the traditional TEF methodologies that sum all dioxin-like PCDDs, PCDFs, and PCBs
and compare site contaminant levels to calculated protective values of 2,3,7,8-TCDD.
Follow the recommendations in:
Section 8.0: Step-by-step procedure for calculating site-specific dioxin, furan, and PCB
ecologically protective cleanup levels and determining compliance (when using methods
other than MTCA Table 749-2 or Table 749-3).
Ready to determine if contaminants are of ecological concern? See:
Section 5.0: How to determine if dioxins, furans, or PCBs are contaminants of
ecological concern.
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Concluded that dioxin-like PCDD, PCDF, and PCBs are not a concern at the
site?
Reference the following sections to determine total PCBs using EPA Method 8082 for
comparison with WAC 173-340-900 screening levels:
Section 3.0: General procedure for determining compliance for dioxins, furans, and
PCBs using the TEE table values in WAC 173-340-900.
Section 6.0: What method do I use to analyze PCBs?
Section 7.0: Step-by-step procedure for determining compliance for mixtures of PCBs
using the tables in WAC 173-340-900 and EPA Method 8082.
2.6 TEQ Methodology for Ecological Risk Assessment
TEF’s are used to convert dioxin, furan, and PCB congener concentrations to TEQ’s. Each
congener is adjusted by its TEF to calculate a TEQ concentration, which expresses the
concentration of that congener as if it were present in the form of TCDD. The TEQ
concentrations for all the congeners are summed, then the total TEQ concentration is compared
to the concentration of 2,3,7,8-TCDD that has been determined to be protective of the ecological
receptor(s) of interest.
Mammalian TEF’s should only be used for calculating TEQs for the mammalian predators
(shrew) and mammalian herbivores (vole). Avian TEF’s should be used for calculating TEQs
for the avian predators (robin). Table 2 summarizes the TEF values to be used for an Ecological
Risk Assessment. Either direct comparison or statistical methods (as described in WAC 173-
340-740 (7)) may be used for evaluating compliance.
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Table 2: PCDD, PCDF, and PCB toxicity equivalency factors for mammals and avians
CAS Number
Hazardous Substance
Mammalian TEF(1)*
Avian TEF(1)
Dioxin Congeners
1746-01-6 2,3,7,8-Tetrachloro dibenzo-p-dioxin 1 1
40321-76-4 1,2,3,7,8-Pentachloro dibenzo-p-dioxin 1 1
39227-28-6 1,2,3,4,7,8-Hexachloro dibenzo-p-dioxin 0.1 0.05
57653-85-7 1,2,3,6,7,8-Hexachloro dibenzo-p-dioxin 0.1 0.01
19408-74-3 1,2,3,7,8,9-Hexachloro dibenzo-p-dioxin 0.1 0.1
35822-46-9 1,2,3,4,6,7,8-Heptachloro dibenzo-p-dioxin 0.01 <0.001
3268-87-9 1,2,3,4,6,7,8,9-Octachloro dibenzo-p-dioxin 0.0003 0.0001
Furan Congeners
51207-31-9 2,3,7,8-Tetrachloro dibenzofuran 0.1 1
57117-41-6 1,2,3,7,8-Pentachloro dibenzofuran 0.03 0.1
57117-31-4 2,3,4,7,8-Pentachloro dibenzofuran 0.3 1
70648-26-9 1,2,3,4,7,8-Hexachloro dibenzofuran 0.1 0.1
57117-44-9 1,2,3,6,7,8-Hexachloro dibenzofuran 0.1 0.1
72918-21-9 1,2,3,7,8,9-Hexachloro dibenzofuran 0.1 0.1
60851-34-5 2,3,4,6,7,8-Hexachloro dibenzofuran 0.1 0.1
67562-39-4 1,2,3,4,6,7,8-Heptachloro dibenzofuran 0.01 0.01
55673-89-7 1,2,3,4,7,8,9-Heptachloro dibenzofuran 0.01 0.01
39001-02-0 1,2,3,4,6,7,8,9-Octachloro dibenzofuran 0.0003 0.0001
PCB Congeners
32598-13-3 3,3’,4,4’ TetraCB (77) 0.0001 0.05
70362-50-4 3,4,4’,5 TetraCB (81) 0.0003 0.1
32598-14-4 2,3,3’,4,4’ PeCB (105) 0.00003 0.0001
74472-37-0 2,3,4,4’,5 PeCB (114) 0.00003 0.0001
31508-00-6 2,3’,4,4’,5 PeCB (118) 0.00003 0.00001
65510-44-3 2’,3,4,4’5 PeCB (123) 0.00003 0.00001
57465-28-8 3,3’4,4’,5 PeCB (126) 0.1 0.1
38380-08-4 2,3,3’,4,4’,5 HxCB (156) 0.00003 0.0001
69782-90-7 2,3,3’,4,4’,5’ HxCB (157) 0.00003 0.0001
52663-72-6 2,3’,4,4’,5,5’ HxCB (167) 0.00003 0.00001
32774-16-6 3,3’,4,4’,5,5’ HxCB (169) 0.03 0.001
39635-31-9 2,3,3’,4,4’,5,5’ HpCB (189) 0.00003 0.00001
(1) Source: Van den Berg, et al. (2006) and Van den Berg et al. (1998). The 2005 World Health
Organization re-evaluation of human and mammalian toxicity equivalency factors for dioxins and dioxin-
like compounds. Toxicological Sciences, 2006 93(2), 223-241; doi:10.1093/toxsci/kfl055.
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3.0 General Procedures for Determining Compliance for
Dioxins, Furans, and PCBs using the TEE Table Values in
WAC 173-340-900
Table 3: General procedures for determining compliance for dioxins, furans, and PCBs using the TEE table values in WAC 173-340-900
To Determine Compliance for
Use this Procedure Procedure
No.
Dioxin congeners
Compare the sum of the TEF-adjusted concentrations (TEQ) for the seven (7) dioxin congeners to the appropriate screening level (Table 749-2 or Table 749-3, as appropriate for the site) for “chlorinated dibenzo-p-dioxins (total).”
1
Furan congeners
Compare the TEQ for the ten (10) furan congeners to the appropriate screening level (Table 749-2 or Table 749-3) for “chlorinated dibenzofurans (total).”
2
To Measure Use this Procedure Procedure
No.
Total PCB concentrations using EPA Method 8082
Compare the total Aroclors (no adjustments using TEFs) to the “PCB mixtures (total)” screening level (Table 749-2 or Table 749-3).
3
PCB congeners using EPA Method 1668
Compare the total PCB Congener Analysis (no adjustments using TEFs) to the “PCB mixtures (total)” screening level (Table 749-2 or Table 749-3);
AND
4A
Compare the sum of the TEQs equivalency for the twelve (12) dioxin-like PCB congeners to the appropriate screening level (Table 749-2 or Table 749-3) for “chlorinated dibenzo-p-dioxins (total).”
4B
Mixtures of dioxin, furans and PCBs
Use Procedure 4A (above) to calculate and compare a “PCB mixtures (total)” screening level (Table 749-2 or Table 749-3);
AND
5A
Use Procedures 1, 2, and 4B (above) for each component of the dioxin, furan, and dioxin-like PCB congeners.
5B
Summary:
1. Adjust the concentration of each congener by the appropriate TEF. 2. Sum to calculate a total TEQ concentration (which includes dioxins, furans,
and dioxin-like PCBs). 3. Compare this total TEQ concentration with the screening level (Table 749-2
or Table 749-3) for “chlorinated dibenzo-p-dioxins (total).”
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Figure 3: Summary of calculating contaminant levels for use when comparing screening levels to MTCA Table 749-2 or 749-3. Methods include EPA Method 1613 (USEPA 1994) for Dioxin/Furan analysis, and EPA Methods 1668 (USEPA 2008) and EPA Method 8082 (USEPA 2007) for PCB analysis.
Note: Total Aroclors (USEPA Method 8082) is an acceptable method to determine Total PCB concentrations. However, only PCB Congener
Analyses (EPA Method 1668) should be used to evaluate the 12 dioxin-like PCB congeners at the site.
Screening Levels
Dioxins
USEPA Method 1613: Sum the TEF
Equivalency products of the 7 dioxin congeners
Compare to Screening Level: Chlorinated dibenzo-p-dioxins
(total):
(Table 749-2 or 749-3)
Furans
USEPA Method 1613: Sum the TEF
Equivalency products of the 10
dioxin-like furan congeners
Compare to Screening Level: Chlorinated
dibenzofurans (total):
(Table 749-2 or 749-3)
PCBs
Total PCBs Only
USEPA Method 8082
Compare to Screening Level: PCB Mixtures
(total):
(Table 749-2 or 749-3)
Total PCBs and Dioxin-Like PCBs
USEPA Method 1668
Total PCBs: USEPA Method 1668
Compare to Screening Level: PCB
Mixtures (total):
(Table 749-2 or Table 749-3)
USEPA Method 1668: Sum the TEF Equivalency products of the 12 dioxin-
like PCB congeners
Compare to Screening Level: Chlorinated dibenzo-p-dioxins
(total):
(Table 749-2 or 749-3)
OR
+
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4.0 Step-by-Step Procedure for Determining Compliance for
Mixtures of Dioxins, Furans, and PCBs Using the TEE Table
Values in WAC 173-340-900 and EPA Method 1668
Overview:
When establishing and determining compliance using the screening level tables in WAC 173-
340-900, mixtures of dioxins should be considered a single hazardous substance, mixtures of
furans should be considered another separate single hazardous substance, and mixtures of PCBs
shall be considered a third separate single hazardous substance.
Which screening levels should be used to determine compliance?
Use the Simplified TEE screening levels (MTCA Table 749-2) only at sites where it
has been determined that a Simplified TEE (WAC 173-340-7492) will meet the
Ecological Risk Assessment requirements of WAC 173-340.
Use the Site-Specific TEE screening levels (MTCA Table 749-3) at any site.
_____________________________________________________________________________
Step 1. Calculate the total TEQ for the dioxin congeners.
For each of the seven (7) dioxin congeners, multiply the individual congener
analytical result by the appropriate TEF. Sum the resulting calculations to determine
a total TEQ for the dioxin congeners.
Step 2. Compare the PQL/EQLs for each dioxin congener to the quantitation limits
established in Implementation Memo No. 11.
Review the Laboratory Quality Assurance Project Plan (QAPP) to verify that the
Laboratory Quantitation Limit (PQL/EQL) for each dioxin congener is at (or lower
than) the Quantitation Limit established for each congener listed in Ecology’s
Implementation Memo No. 11: Dioxins, Furans, and Dioxin-Like PCB Congeners:
Addressing Non-Detects and Establishing PQLs for Ecological Risk Assessments in
Upland Soil (Ecology 2015a).
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Step 3a. If the following four criteria have been met, assign non-detected congeners a
value of one-half (1/2) the detection limit for compliance calculations:
Congener has been detected at the site (EDL);
Congener is not detected in the sample of concern (EDL);
Lab PQL/EQL detection limits are no greater than the PQL/EQL established in
Ecology Implementation Memo No. 11; and
The department does not require a lower quantitation limit as per WAC 173-340-
830(2) (e).
Step 3b. If the following three criteria have been met, assign non-detected congeners a
value of zero (0) for compliance calculations:
Congener is not detected in any sample at the site (EDL);
Lab PQL/EQL detection limits are no greater than the PQL/EQL established in
Ecology Implementation Memo No. 11; and
The department does not require a lower quantitation limit as per WAC 173-340-
830(2) (e).
Step 3c: If the following conditions apply, other approved statistical procedures can be
used, such as the Kaplan-Meier (KM) Product Limit Estimator for the treatment
of non-detected congeners (USEPA, 2011) (Ecology 2015a):
Some fraction of the congeners are non-detect; and
There are at least three detected congeners.
Step 4. Calculate the total TEQ for the furan congeners.
For each of the ten (10) furan congeners, multiply the individual congener analytical
result by the appropriate TEF. Sum the resulting calculations to determine a total
TEQ for the furan congeners.
Step 5. Compare the PQL/EQLs for each furan congener to the quantitation limits
established in Implementation Memo No. 11.
Review the Laboratory QAPP to verify that the Laboratory PQL/EQL for each furan
congener is at (or lower than) the Quantitation Limit established for each congener
listed in Ecology Implementation Memo No. 11 (Ecology 2015a).
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Step 6a: If the following four criteria have been met, assign non-detected congeners a
value of one-half (1/2) the detection limit for compliance calculations:
Congener has been detected at the site (EDL);
Congener is not detected in the sample of concern (EDL);
Lab PQL/EQL detection limits are no greater than the PQL/EQL established in
Ecology Implementation Memo No. 11; and
The department does not require a lower quantitation limit as per WAC 173-340-
830(2) (e).
Step 6b: If the following three criteria have been met, assign non-detected congeners a
value of zero (0) for compliance calculations:
Congener is not detected in any sample at the site (EDL);
Lab PQL/EQL detection limits are no greater than the PQL/EQL established in
Ecology Implementation Memo No. 11; and
The department does not require a lower quantitation limit as per WAC 173-340-
830(2) (e).
Step 6c. If the following conditions apply, other approved statistical procedures can be
used (such as the Kaplan-Meier (KM) Product Limit Estimator for the
treatment of non-detected congeners (USEPA 2011) (Ecology 2015a):
Some fraction of the congeners are non-detect; and
There are at least three detected congeners.
Step 7. Calculate the total TEQ for the dioxin-like PCB congeners.
For each of the twelve (12) dioxin-like PCB congeners, multiply the individual
congener analytical result by the appropriate TEF. Sum the resulting calculations to
determine a total TEQ for the PCB congeners.
Step 8. Compare the PQL/EQLs for each dioxin-like congener to the quantitation limits
established in Implementation Memo No. 11.
Review the Laboratory QAPP to verify that the Laboratory PQL/EQL for each
dioxin-like congener (PCDD, PCDF, PCB) is at (or lower than) the Quantitation
Limit established for each congener listed in Ecology Implementation Memo No. 11
(Ecology 2015a).
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Step 9a. If the following four criteria have been met, assign non-detected congeners a
value of one-half (1/2) the detection limit for compliance calculations:
Congener has been detected at the site (EDL).
Congener is not detected in the sample of concern (EDL);
Lab PQL/EQL detection limits are no greater than the PQL/EQL established in
Ecology Implementation Memo No. 11; and
The department does not require a lower quantitation limit as per WAC 173-340-
830(2) (e).
Step 9b. If the following three criteria have been met, assign non-detected congeners a
value of zero (0) for compliance calculations:
Congener is not detected in any sample at the site (EDL);
Lab PQL/EQL detection limits are no greater than the PQL/EQL established in
Ecology Implementation Memo No. 11; and
The department does not require a lower quantitation limit as per WAC 173-340-
830(2) (e).
Step 9c. If the following conditions apply, other approved statistical procedures can be
used, such as the Kaplan-Meier (KM) Product Limit Estimator for the treatment
of non-detected congeners (USEPA 2011) (Ecology 2015a):
Some fraction of the congeners are non-detect; and
There are at least three detected congeners.
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5.0 How do I determine if dioxins, furans or PCBs are
contaminants of ecological concern?
Table 4: How to determine if dioxins, furans, or PCBs are contaminants of ecological concern
To determine if these contaminants are of ecological concern:
Compare:
To the appropriate WAC 173-340-900 screening levels
(Table 749-2 or 749-3) for:
Dioxins Total TEQ for dioxin congeners
“Chlorinated dibenzo-p-dioxins (total)”
Furans Total TEQ for furan congeners
“Chlorinated dibenzofurans (total)”
Dioxin-like PCBs
Total TEQ for dioxin-like PCB congeners
AND
“Chlorinated dibenzo-p-dioxins (total)”
AND
Total PCBs Total PCB Congener Analysis (no adjustments using TEFs)
“PCB mixtures (total)”
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6.0 What method do I use to analyze PCBs?
Overview:
Reference Implementation Memo No. 12, When to Use EPA Method 1668 for PCB Congener
Analyses for a summary of PCB Analyses (Ecology 2015b).
There are two basic approaches for evaluating the ecological risks associated with environmental
concentrations of PCBs:
Total PCB Concentration using EPA Method 8082 and
Congener Specific Analyses using EPA Method 1668.
_________________________
Step 1. Are dioxin-like congeners NOT suspected at a site? Use Total PCB
Concentration EPA Method 8082.
See Section 7.0 for the procedure. NOTE: The determination that EPA Method
8082 will sufficiently test for PCBs at your site should be discussed with your
Ecology Cleanup Project Manager.
BACKGROUND: Under the MTCA Cleanup Regulation, site contaminant
concentrations for comparing to screening levels (Table 749-2 and Table 749-3) for
PCB mixtures can be calculated using measurements of total PCB concentrations in
environmental media. This can be done using standard methods involving gas
chromatography/electron capture detection systems. Specifically, total PCB
concentrations are estimated by comparing the chromatographic pattern of peaks in
the environmental sample to the pattern or number of peaks in a commercial Aroclor
sample. With this approach, the total of all Aroclors reported for the sample would
be compared to the WAC 173-340-900 (Table 749-2 or 749-3) screening level for
“PCB mixtures (total),” to determine if PCBs are a contaminant of ecological
concern.
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Step 2. Are dioxin-like congeners suspected at a site? Use Congener Specific Analyses
EPA Method 1668.
See Section 7.0 for the procedure.
BACKGROUND: PCB mixtures may include up to 209 individual congeners that
differ in the number and location of chlorine atoms. Over the last 30 years, the
standard approach for estimating PCB environmental concentrations has begun to
shift from the analysis of commercial mixtures (Aroclors, identified above) to
congener-based analyses. Dioxins and furans are generally present in the
environment as complex mixtures of chemical “congeners” that differ in the number
and location of chlorine atoms. Using this approach, the total PCB concentrations are
compared to the WAC 173-340-900 (Table 749-2 or 749-3) screening level for “PCB
mixtures (total).” The summed dioxin-like TEQ calculation are compared to the
WAC 173-340-900 (Table 749-2 or 749-3) screening level for “Chlorinated dibenzo-
p-dioxins (total)” to determine if dioxin-like PCBs are a contaminant of ecological
concern:
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7.0 Step-by-Step Procedure for Determining Compliance for
Mixtures of PCBs Using the Tables in WAC 173-340-900 and
EPA Method 8082 or EPA Method 1668
Overview:
When establishing and determining compliance using screening level tables in WAC 173-340-
900, PCBs shall be considered a single hazardous substance.
Which screening level should be used to determine compliance?
Use the Simplified TEE screening levels (MTCA Table 749-2) only at sites where it
has been determined that a Simplified TEE (WAC 173-340-7492) will meet the
Ecological Risk Assessment requirements of WAC 173-340.
Use the Site-Specific TEE (MTCA Table 749-3) at any site.
___________________________
EPA Method 8082:
Step 1: Calculate total PCBs by summing Total Aroclors as listed in Table 1 of
Implementation Memo No. 12, When to Use EPA Method 1668 for PCB Congener
Analyses.
Step 2: Determine if PCBs are a contaminant of ecological concern:
Reference the procedures found in Table 3, Section 3.0 of this memo.
Use Procedure No. 3 to compare Total Aroclors (from Step 1 above) to the
appropriate WAC 173-340-900 screening level in Table 749-2 or 749-3 for “PCB
mixtures (total)” to determine if PCBs are a contaminant of ecological concern.
EPA Method 1668:
Step 1: Calculate total PCBs by summing EPA Method 1668 total PCB Congener Analysis
(209 congeners).
Step 2: Determine if PCBs are a contaminant of ecological concern: Reference the
procedures found in Table 3, Section 3.0 of this memo and compare Total PCB
concentrations to the appropriate WAC 173-340-900 screening level (Table 749-2 or
749-3) for “PCB mixtures (total)” to determine if PCBs are a contaminant of
ecological concern.
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8.0 Step-by-Step Procedure for Calculating Site-Specific
Dioxin, Furan, and PCB Ecologically Protective Cleanup
Levels and Determining Compliance
(When Using Methods other than
MTCA Tables 749-2 or Table 749-3)
Overview:
When it has been determined to use protective cleanup levels other than Tables 749-2 and 749-3,
the seven (7) PCDD congeners, ten (10) PCDF congeners, and twelve (12) dioxin-like PCB
congeners should be considered a single hazardous substance.
Multiply the concentration of each congener by its TEF to calculate the congener-specific
TEQ.
Sum the congener-specific TEQs to calculate the total TEQ.
Compare the total TEQ with a 2,3,7,8-TCDD contaminant level that has been determined
to be protective of ecological receptors (plants, soil biota, wildlife).
_________________
Step 1. Calculate the total TEQ for the congeners using Equation 1 (see equation
following these steps).
Calculate the TEQ of each of the seven (7) dioxin, ten (10) furan, and twelve (12)
PCB congeners by multiplying the individual congener analytical results by the
appropriate TEF, as seen in Table 2 of this document. Sum the resulting calculations
to determine the total TEQ.
Step 2. Compare PQL/EQLs for each dioxin-like congener to quantitation limits found
in Implementation Memo No. 11.
Review the QAPP to verify that the Laboratory Quantitation Limit (PQL/EQL) for
each dioxin-like congener (PCDD, PCDF, PCB) is at (or lower than) the Quantitation
Limit established for each congener listed in Ecology Implementation Memo No. 11,
Dioxins, Furans, and Dioxin-Like PCB Congeners: Addressing Non-Detects and
Establishing PQLs for Ecological Risk Assessments in Upland Soil (Ecology 2015a).
Washington State Department of Ecology Toxics Cleanup Program Implementation Memo #13
Publication No. 16-09-044 (July 2016) Page 22
Step 3a. If the following four criteria have been met, assign non-detected congeners a
value of one-half (1/2) the detection limit for compliance calculations:
Congener has been detected at the site (EDL);
Congener is not detected in the sample of concern (EDL);
Lab PQL/EQL detection limits are no greater than the PQL/EQL established in
Ecology Implementation Memo No. 11; and
The department does not require a lower quantitation limit as per WAC 173-340-
830(2) (e).
Step 3b. If the following three criteria have been met, assign non-detected congeners a
value of zero (0) for compliance calculations:
Congener is not detected in any sample at the site (EDL);
Lab PQL/EQL detection limits are no greater than the PQL/EQL established in
Ecology Implementation Memo No. 11; and
The department does not require a lower quantitation limit as per WAC 173-340-
830(2) (e).
Step 3c. If the following conditions apply, other approved statistical procedures can be
used (such as the Kaplan-Meier (KM) Product Limit Estimator for the
treatment of non-detected congeners, USEPA 2011) (Ecology 2015a):
If some of the congeners are non-detect; and
There are at least three detected congeners.
Step 4. Compare total TEQ calculation to 2,3,7,8-TCDD contaminant level.
Compare the total TEQ calculation with a 2,3,7,8-TCDD contaminant level that has
been determined to be protective of ecological receptors (plants, soil biota, wildlife)
through methods listed in WAC 173-340-7493(3)(a) through (g) [Selection of
appropriate terrestrial ecological evaluation methods].
__________________________
Washington State Department of Ecology Toxics Cleanup Program Implementation Memo #13
Publication No. 16-09-044 (July 2016) Page 23
Equation 1: Calculating TEQ concentrations in samples. (Van den Berg et al., 1998)
TEQ = ∑ (PCDDi x TEFi) + ∑ (PCDFi x TEFi) + ∑ (PCBi x TEFi)
Where:
PCDD = Polychlorinated dibenzo-p-dioxin
PCDF = Polychlorinated dibenzofuran
PCB = Polychlorinated biphenyl
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9.0 References
Butte Environmental Council. (2012). Dioxin binding with the Ah receptor. Retrieved from:
http://www.becnet.org/ and
www.becnet.org/sites/default/files/file-attachment/DioxinBindingWiththeAhReceptor.pdf
Ecology. (2007a). Model Toxics Control Act statute and regulation, Chapter 173-340 WAC.
(Ecology Publication No. 94-06). Lacey, WA: Washington State Department of Ecology, Toxics
Cleanup Program. Retrieved from:
https://fortress.wa.gov/ecy/publications/SummaryPages/9406.html and
http://apps.leg.wa.gov/WAC/default.aspx?cite=173-340-7490
Ecology. (2007b). Concise explanatory statement and responsiveness summary for the
amendment of Chapter 173-340, Model Toxics Control Act Cleanup Regulation. (Ecology
Publication No. 07-09-108). Lacey, WA: Washington State Department of Ecology, Toxics
Cleanup Program. Retrieved from:
https://fortress.wa.gov/ecy/publications/SummaryPages/0709108.html
Ecology. (2007c). Background document for the proposed amendments to the Model Toxics
Control Act Cleanup Regulation, Chapter 173-340 WAC. (Ecology Publication No. 07-09-050).
Lacey, WA: Washington State Department of Ecology, Toxics Cleanup Program. Retrieved
from:
https://fortress.wa.gov/ecy/publications/SummaryPages/0709050.html
Ecology. (2014). Polychlorinated Biphenyls (PCBs) in general consumer products. (Ecology
Publication No. 14-04-035). Lacey, WA: Washington State Department of Ecology, Hazardous
Waste and Toxics Reduction Program. Retrieved from:
https://fortress.wa.gov/ecy/publications/SummaryPages/1404035.html
Ecology. (2015a). Dioxins, furans, and dioxin-like PCB congeners: Addressing non-detects and
establishing PQLs for ecological risk assessments in upland soil, Implementation Memorandum
No. 11. (Ecology Publication No. 15-09-048). Lacey, WA: Washington State Department of
Ecology, Toxics Cleanup Program. Retrieved from:
https://fortress.wa.gov/ecy/publications/SummaryPages/1509048.html
Ecology. (2015b). When to use EPA Method 1668 for PCB congener analyses, Implementation
Memorandum No. 12. (Ecology Publication No. 15-09-052). Lacey, WA: Washington State
Department of Ecology, Toxics Cleanup Program. Retrieved from:
https://fortress.wa.gov/ecy/publications/SummaryPages/1509052.html
Gueguen M., Amiard, J.C., Arnich N., Badot, P.M., Claisse, D., Guerin, T., & Vernoux, J.P.
(2011). Shellfish and residual chemical contaminants: Hazards, monitoring, and health risk
assessment along French coasts. Reviews of Environmental Contamination and Toxicology.
213, 55-111.
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USEPA. (1994). Method 1613: Tetra- through octa-chlorinated dioxins and furans by isotope
dilution HRGC/HRMS. (No publication number). Washington, D.C.: United States
Environmental Protection Agency, Office of Water Engineering and Analysis Division.
USEPA. (2007). Method 8082A: Polychlorinated biphenyls (PCBs) by gas chromatography.
(No publication number). Washington, D.C.: United States Environmental Protection Agency.
USEPA. (2008). Method 1668B: Chlorinated biphenyl congeners in water, soil, sediment,
biosolids, and tissue by HRGC/HRMS. (No publication number). Washington, D.C.: United
States Environmental Protection Agency.
USEPA. (2008). Framework for application of the Toxicity Equivalence Methodology for
polychlorinated dioxins, furans, and biphenyls in ecological risk assessment. (EPA 100/R-
08/004). Washington, D.C.: United States Environmental Protection Agency.
USEPA. (2011a). User guide: Uniform federal policy quality assurance project plan for soils
assessment of dioxin sites. (No document number). Washington, D.C.: United States
Environmental Protection Agency.
USEPA. (2011a). User guide: Uniform federal policy quality assurance project plan template for
soils assessment of dioxin sites. (No document number). Washington, D.C.: United States
Environmental Protection Agency.
USEPA. (2013). Polychlorinated Biphenyls (PCBs): Basic information. Washington, D.C.:
United States Environmental Protection Agency. Retrieved from:
http://www.epa.gov/epawaste/hazard/tsd/pcbs/about.htm
Van den Berg, M., Birnbaum, L., Bosveld, A., Brunstrom, B., Cook, P., Feeley, M. . . .
Zacharweski, T. (1998, December). Toxic equivalency factors (TEFs) for PCBs, PCDDs,
PCDFs for humans and wildlife. Environmental Health Perspectives, 106(12).
Van den Berg, M., Birnbaum, L., Denison, M., De Vito, M., Farland, W., Feeley, M. . . .
Peterson, R. (2006). The 2005 World Health Organization reevaluation of human and
mammalian toxic equivalency factors for dioxins and dioxin-like compounds. Toxicological
Sciences, 93(2), 223-241, doi:10.1093/toxsci/kfl055